1. Field of the Invention
The present invention relates to ultrasonic temperature measurement and more particularly to a novel ultrasonic temperature sensor using a high Q mechanical resonator, and to an arrangement for temperature measurement including an operating circuit for the sensor in which accuracy is enhanced by the Q of the resonant sensor.
2. Description of the Prior Art
It is well known that the elastic modulus of a material is temperature dependent, that the temperature may be measured by measuring the velocity of propagation of acoustic waves in the material. The most common method of measurement is to use a transit time or time of flight measurement, in which reflections are produced at two different locations in a sensing element. The time of flight method is simple, but the customary accuracy, assuming a given electronic timing accuracy, is then set by the length of the sensing element between the two locations giving rise to the reflections. If a short sensing region is desired, e.g. 1/2 to 1/4 of an inch, one may expect an accuracy in temperature measurement of about 2 degrees C.